Debatable.
If Little Kim, under pressure from sanctions, started lobbing missiles into SK, would that not be a trip wire? Do we not have interests in the region and interests in not allowing piss ant dictators from firing off against the 'paper tiger'?
Do we not have billions invested in the Persian gulf region in the form of oil industry? Do we not have some obligation to those US interests and the US personnel who are over there?
Finally, do we not have a duty to keep shipping lanes free and open? (answer, yes we do)
Iran's actions over the last many months are direct threats and actions against all of these so 'this is not our fight' is a debatable subject.
The US people are tired of being the worlds police, and not interested in getting in more protracted wars, but we also aren't interested in sticking our heads in the ground while some raghead is kicking us in the ass. Sometimes your enemy doesn't give you much choice but to hit back.
Well, when Saudi Arabia and Pakistan attacked us in 2001, not only did we decline to hit back, we took out that Saudi's main enemy.
Think we're going to do it again?
OK, debatable. We disagree but it really doesn’t matter anyway. We don’t get a say in the matter.